1. Field of the Invention
The present invention relates to a print output system, a print control apparatus and a print control method which are configured to control print output by a plurality of printing apparatuses.
2. Description of the Related Art
A conventional printing apparatus such as a digital copying machine, a laser beam printer (LBP), a facsimile apparatus is connected to a network and printout is executed by sending documents or images from a personal computer connected to the network to the printing apparatus. The printing apparatus can be set so that when it is not manipulated and operated within a predetermined time, for example, on the operation panel, power supply is stopped to a fixing device or the like which has high power supply, and the printing apparatus transits to a sleep state (power saving mode) which is configured to suppress power consumption for the overall apparatus.
In a conventional print output system, since the conditions for shifting to power saving mode vary depending on each apparatus, comprehensive power saving management of a printing apparatus connected to a specified network has been difficult. For example, it is assumed that there are two printers connected to a plurality of personal computers, one printer is operating and the other printer is in power saving mode. When a print output signal is output from another personal computer, normally, the printer in power saving mode is operated. The image processing apparatus proposed in Japanese Patent Application Laid-Open No. 2001-197297 determines a sleep condition for a printer, and when print output is not urgent, waits for completion of the current print job (JOB) performed by the currently operating printer. Thereafter the plurality of printing apparatuses connected to the network is controlled to execute new printing jobs.
Although the conventional technique takes the state of the printing apparatus into account, the characteristics of the printing apparatus are not considered. Thus when a plurality of printing apparatuses with mutually different characteristics are present on a network, there is the situation that overall power consumption actually increases. For example, currently, a fixing device constituting a digital copying machine employs the fixing method illustrated in FIG. 3A or the fixing method illustrated in FIG. 3B as described hereafter. The fixing method in FIG. 3A is of a roller type and the fixing method in FIG. 3B is of an on-demand type.
FIG. 13 illustrates the characteristics of the fixing device and the relationship between temperature and printing for each fixing method. FIG. 13A illustrates the characteristics of an on-demand type and a roller type. Generally, a roller type has high power consumption and a high printing speed. An on-demand type has low power consumption and a low printing speed. FIG. 13B conceptually illustrates the relationship between printing and the temperature of a fixing device in a digital copying machine based on mutually different fixing methods. In contrast to a digital printing apparatus provided with a fixing device on the basis of an on-demand type fixing method, a digital copying machine provided with a fixing device on the basis of a roller-type fixing method is maintained at high temperature (standby state), which results in high power consumption even after execution of printing. If a new print job is started again within the period from standby to a low-temperature state (sleep state), the high-temperature state further continues, which results in high power consumption. Therefore when an on-demand type and a roller-type digital copying machine are both present in a print output system, in order to suppress power consumption, the characteristics of the printing apparatuses is to be sufficiently considered.
Further, the conventional technique does not consider an operation state or operation rate in addition to characteristics such as the fixing method of the printing apparatus when determining an apparatus to execute print output. Thus in the conventional technique, for example, there is a situation such as an increase in the power consumption of the overall system resulting from biased selection of a roller-type printing apparatus, which has high power consumption as the apparatus to execute print output. A further situation is that printing efficiency of the overall system cannot be increased due to biased selection of an on-demand type printing apparatus which has low power consumption but a slow printing speed as the apparatus to execute print output.